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Engine & cooling

2020 Subaru Legacy Engine problems

Owners have filed 4 complaints about the 2020 Subaru Legacy's engine & cooling with NHTSA - 3% of all its complaints, most recently on July 16, 2025. They describe 0 crashes, 1 fire and 0 injuries. Stalling, loss of power, oil consumption, overheating, head gaskets, timing chains and engine failure.

Complaints
4
Recalls
0
Crashes
0
Fires
1
Injuries
0
Deaths
0

Engine complaints

Electrical systemEngine & coolingFire

One hour into traveling on the highway smoke began to come from under the hood so we pulled off to the side of the road. Upon opening the hood, after the smoke cleared, a fire was observed. At that point the passengers exited the vehicle and called 911. There was no warning lights or sounds indicating any problems prior to this. The car burned very quickly and the firefighters extinguished the fire but not before the entire car was burned to ashes. The car is wrapped and in the possession of the insurance company pending investigation.

Filed Incident Electrical system · EngineNHTSA 11674078
Engine & cooling

The engine thermo control valve has been defective and Subaru has known this issue since 2022 and has tried to do some software update but it is defective [[redacted]] ) despite multiple tries. This can overheat an engine, result in the front collision warning system (eyesight) and rear auto-braking not working. Specific to my case, the front and rear collision warning systems are off, auto lane departure avoidance system is off, the engine can overheat and has had reduced performance, and the check engine lights are also on. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Incident EngineNHTSA 11565945
Electrical systemEngine & cooling

Thermo Control Valve has malfunctioned. It disables all driver assistance, like lane assist, blind spot, RAB, collision braking, etc. I have seen on many forums that this is a known issue, across multiple vehicles from Subaru from 2019 to about 2021. The was a TSB put out about a new and improved part to fix this known issue.

Filed Incident Electrical system · EngineNHTSA 11544993
Transmission & drivetrainEngine & cooling

Check engine light came on at 55,500 miles on exactly the third anniversary of purchase. Local mechanic determined the code related to Thermo Control Valve failure. Apparently an ongoing issue with many Subarus since replacing the thermostat with this in their cars. Lost all eyesight features, including cruise control and high beams, as well as cabin heat in the midst of winter in the northeast. A simple google search reveals MANY instances of this subpar part falling on Subaru cars. $1,066 later, I feel a recall or coverage under powertrain warranty is warranted.

Filed Incident Power train · EngineNHTSA 11509131

Subaru Legacy engine complaints by year

Legacy engine problems, every year

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Source: U.S. National Highway Traffic Safety Administration (NHTSA) complaints and recalls, checked . Complaints are owners' own reports and are not verified. How we use the data

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